Chain for wood-pulp grinders



May 7, L929: J. E. BURKHARDT CHAIN FOR WOOD PULP GRINDERS Filed Nov. 8, 1924 MMMM M ATTORNEYS Patented May 7, 1929.

llhll'lED STATES JOHN ERNEST BUBI ZHARDT, OF BATH, MAINE, AhSIGI TOlE BROWNVILLE, YORK.

TO JOHN J. WARREN, O1?

CHAIN FOR WOOD-PULP Application filed November 8, 1924, Serial No. 7%,617, and in Clanada October E8, 1924,

This invention relates to feed chains particularly adapted for use in wood pulp indrrs, ot the magazine type.

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llnitcd Stator-i Patent No. 1,465,069, the inventor has described a wood-pulp ulcr of the magazine type in which the wood continuously forced against the pgrindstone by means of endless feed chains \r'llltll move down the inner face of the magazine, and grip the wood by means of projecting); spurs situated at the forward or lower ends of the chain links. By reason of the fact that these projections are situated at the forward ends of thelinks they are swung away from the wood as the chains turn about their lower sprockets, whereas it they were placed on the rear or upper ends of the links they would tear into the wood at that point, thus not only consuming: power unnecessarily, but making slivers, l have ound these chains to operate well in prac e. The specilic form illustrated in the patent, however, .is relatively expensive to nninuiiacture inasmuch as the projecting, wood-gripping spurs are not integral with the links but are affixed thereto. It is therefore an object of the present invention to design a feed chain the links of which, with their associated spurs, can be made less expensively than the separate spur type. T attain this object by forging both .lin and spur from a single piece of metal. This construction is not only cheaper than the one illustrated inthe patent, but being unitary is also somewhat more rugged.

The actual wood-grippingface of the spurs illustrated in the patent is also relatively narrow, which, although suflicient when working with firm, sound wood is likely to cause the spurs to crush through the soft and rotten logs which must sometimes be'ground. It is a further object of this invention to design a feed chain adapted for use in grinding soft or rotten wood. I attain this object by widening the woodcontacting face of the spurs so that the pressure exerted by them is distributed over a ,{greater area of the wood.

l t is a further object of the invention to make a generally improved chain for the purpose indicated.

In the accompanying drawings I have illustrated certain preferred embodiments of my invention which I shall now describe. Tn these drawings, Figure l isa front elevation of my iuun'ored chain. Figl'u'e 2 is a side elevation of the same chain. Figure 2-5 is a front elevation of a modified form of chain in which the wood-gripping elements are of a somewhat dii'lcrcnt shape, and, Figure t is a perspective view of the lower end of one of the links which go to make up the chain shown in Figure In these drawings I have not illustrator the. woodpulp grinder itself, it being umlerst od that these chains are adapted to operate in a grint or similar tothe one illustrated in the above-mentioned U. S. patent.

The chain illustrated in Figures 1 and 2 comprises a series of parallel links 1 journaled upon connecting pins 2 and. spaced apart by means of cylindrical rollers 23, likewise journaled upon the pins 2. These rollers 23 are adapted to roll upon vertical track-ways on the inner face of the magazinc and prevent contact ofthe chain links therewith. The lower end of each linlc is provided with a spur projection it integral therewith and having a substantially fiat wood-contacting face 5 of a width equal to that of the link ofwhich it forms a part. This wood-contacting face is, however, slightly convex in the plane in which the chain operates, as clearly shown in Figure 2, and is preferably made part of a cylinder the of which is coincident with that of the rear or farther pin of the same link. This facilitates the withdrawal of the spurs from contact with the wood as the links swing outwardly about the lower sprocket with minimum damage to the wood. The horizontal center line of the spurs is also situated well below the center of the pin 2 upon which the lower end of the link in question is journaled. By means of this construction the effective length of each link is increased, which means that the column of wood can be carried just that much closer to the grindstone before the pressure exerted by the lowermost spur is withdrawn. This is advantageous inasmuch as the less the distance intervening between the upper face of the stone and the point where the chains leave the wood, the lessthc opportunity for counter--21rolling, as clearly described in United States Patent lilo. 1,505,757. The triangular form of the spurs and the fact that they are made integral with the links greatly i .creascs their strength.

The chain illustrated in Figures 3 and lis similar to the one in Figures 1 and 2, except that the spurs 4: are extended laterally on either side of the links so that the area of the wood-contacting face 5 is increased. EX ceptfor this difference, the chains are iden tical and function in the same manner.

The links illustrated in these drawings are i preferably made by drop-forging in a manner which is well understood in the art, and winch need not be described in detail here. Among the advantages inherent in my novel chain are the following :First, the

wood-gripping spurs being integral with the links, each complete link can be made more cheaply than a link which is equipped with chains to a point more closely adjacent the stone than would be possible if the spur were situated farther back along the link. Fourth, the wood-contacting face of the spur being slightly convex, preferably having its center of curvature coincident with the center of the farther pin of the same link, is disengaged from the wood as the chain moves about the lower sprocket with a minimum of effort and damage to the wood.' Fifth, the wood-contacting face of the spur i's'not less than the width of the link and asillust-rated in Figures 3 and 4,

may be muclrwider. ,This is particularly advantageous in grinding soft or decayed wood, as it distributes the chain pressure over a larger area and mini mixes the chances of crushing or tearing through the wood.

I claim:

1. A feed chain for wood-pulp grinders comprising aseries of links and wood-contacting projections on the forward ends thereof having wood-contawting faces of a width greater than the thickness of the links.

2. A feed chain for wood-pulp grinders comprising a series of links having woodgripping spurs on the forward ends thereof, the wood gripping face of the spurs being slightly convex in the plane in which the chain operates.

3. A feed chain for wood-pulp grinders comprising a series of links, connecting pins upon which the links are journaled at each end, wood-contacting projections on the for ward ends of the links integral therewith and situated beyond the forward connecting pins.

4. A feed chain for wood-pulp grinders comprising a series of links, and wood-con tacting projections on the forward ends thereof integral therewith and having woodcontacting faces of a width greater than the thickness of the links.

5. A feed chain for wood-pulp grinders comprising a series of links, connecting pins upon which the links are journalcd at each end, wood-contacting projections on the forward ends of the links having cylindrical wood-contacting faces, the axis of each such cylindrical face being coincident with that of the axis of the farther pin of the same link.

In testimony whereof I afiix my signature.

JOHN ERNEST BURKIIAR UT. 

